HTPC and Rotel RSP1068 Interference / Noise

[AngelEyes]

Hey chaps, I hope you can help.

I finally switched from digital coaxial to 7.1 analogue connections between my HTPC and Processor to take advantage of the new sound formats.

Unfortunately the upgrade has introduced a nasty buzzing sound through the speakers. It does not sound like a normal ground loop hum as it changes all the time, as the PC does something or you move the mouse or whatever the sound changes. It is like you 'hear' the processor or HDD working via the speakers.

The buzzing continues when switching to another input but stops once the PC is off. I tried running an 'earth' cable between the PC chassis and the Processor chassis but it was a half arsed attempt and I cannot be sure I really got a good connection, is this worth trying properly or can you suggest anything else?

Also worth noting, when connecting via analogue to my 'cheap' 5.1 speaker package in the office there is no interference at all.

Many thanks,

Adam

PS. I think that the hum was there with the original digital coax connection but was much quieter, hardly noticable.

[aud19]

Sounds like RF interference from one or more of the components in your PC to me. Are you using an aftermarket soundcard or onboard?

[AngelEyes]

Hi Jason,

It is PCI Creative X-FI. I have ruled this out after placing it in another PC where it works fine. I guess I will have to work through the other components somehow or try and shield the sound card...?

Adam

[aud19]

The card's probably picking up RFI from something in that particualr PC...PS, CPU a fan etc. You can try shileding or try to find the offending component and see if it's easily correctable.

[AngelEyes]

I tried shielding the X-FI and unplugging the PC from the Processor but leaving the PC on and you can still just hear the interference but much quieter.

I think it maybe the PSU as I can't imagine any other component generating that much interference without even being connected.

Adam